An antimicrobial is an agent that kills the microorganisms or stops its growth.

There are many different microorganisms and many more sub classes but 5 of the most common microorganisms that are the main causes of infection include:-

1. Bacteria
2. Viruses
3. Fungi
4. Protozoa
5. Parasites

Antimicrobial medicines are grouped according to the what causes the infection they are used to treat:

• Antibiotics e.g. Amoxycillin are used to treat bacterial infections e.g., Pneumonia
• Antivirals e.g. Aciclovir are used to treat viral infections e.g., Herpes Zoster
• Antifungals e.g. Fluconazole are used to treat fungal infections  e.g., Canididiasis
• Antiprotozoals e.g. Chloroquine  are used to treat protozoal infections e.g., Plasmodium Vivax Malaria
• Antiparasitics e.g. Mebendazole are used to treat parasitic infections e.g., Threadworms